[gate-users] splitting a GATE simulation by Activity (or TIME?)

Mutanga Theodore muathe02 at student.umu.se
Thu Nov 4 12:40:30 CET 2004


Greetings, and thanks very much Sophie,

Now at least I have a reasonable idea about how to split the simulation.
What would the setTimeSlice value be in this case ? Take for example the
benchmarkPET example, suppose I want to split it into two simulations ,
what
#	S T A R T
/gate/application/setTimeSlice     120. s *
/gate/application/setTimeStart     0.  s  *
/gate/application/setTimeStop      240. s *
/gate/application/startDAQ                *
*******************************************
job1:
 /gate/application/setTimeStart 0 s
 /gate/application/setTimeStop 120 s

job2
 /gate/application/setTimeStart 120 s
 /gate/application/setTimeStop 240 s

Is the time slice the same ? Would i have to modify other parameters like
the randome number seed ?

Is the number of runs equivalent to the number of histories ?

I will sure like to have  Dirks program to use for combining the root
output files.

thanks for your help


> Hello Theo,
>   Be careful 5 simulations with an activity of 2 Bq is not equivalent to
> one run with 10Bq. The time difference between two events is
> proportional to 1/A so the digitizer will have different effects on a
> small and a high activity.
> The way to split your simulation is to keep a constant activity and
> divide the simulation with time, for instance:
> job1:
> /gate/application/setTimeStart 0 s
> /gate/application/setTimeStop 0.25 s
>
> job2:
> /gate/application/setTimeStart 0.25 s
> /gate/application/setTimeStop 0.5 s
>
> and so on until 1s.
> You will end up with different output files that you should add before
> your final analysis. If you use the root ouput, I have a root program
> (that Dirk has written, thanks to Dirk who give it to me) that I can
> send you if you want).
> Bye
> sophie
>
> On Thu, 2004-11-04 at 11:05, Mutanga Theodore wrote:
>> Hello there,
>>
>> Since no one has answered most of my previous posts, I have been
>> thinking
>> about the problem i have...
>>
>> About splitting a simulation by activity, I was thinking that if for
>> instance i have a big simulation with source of activity 10 Bq, and I
>> want
>> to split the simulation to say five simulations.
>> For the five simulations, can I write five different macros, where in
>> each
>> the source definitions would be
>>     /gate/source/NAME/setActivity 2 Bq   ?
>>
>> And then use
>>            qsub <pbs_submitfile1>
>>            qsub <pbs_submitfile2>
>>            ...
>>            qsub <pbs_submitfile5>
>>
>> ( or a while loop can implement this)
>>
>> where the submitfiles scripts, contains SOURCE ENV_GATE.CSH for setting
>> up
>> the environmental variables needed to run GATe, and the paths to all
>> required files to run GATE, GateMaterials.db etc.
>>
>> About submitting the job(s) there is no problem, I have found out how to
>> do that by preparing the pbs submitfile scripts.
>>
>> I just want to get some clarification on the way I have split the
>> simulations does it look reasonable ? If so do I just merge all the
>> output
>> files (say all the *.root , *.S )at the end of the jobs to generate the
>> root  output and Sinogram output, respectively,  for example  from which
>> I
>> can reconstruct an image ?
>>
>>
>> Thanks for your kind attention , waiting for your asnwers
>>
>> Theo
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>
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